// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.

use deno_core::error::AnyError;
use deno_core::ResourceId;
use deno_core::{OpState, Resource};
use serde::Deserialize;
use std::borrow::Cow;
use std::convert::{TryFrom, TryInto};

use super::error::WebGpuResult;

pub(crate) struct WebGpuBindGroupLayout(
  pub(crate) wgpu_core::id::BindGroupLayoutId,
);
impl Resource for WebGpuBindGroupLayout {
  fn name(&self) -> Cow<str> {
    "webGPUBindGroupLayout".into()
  }
}

pub(crate) struct WebGpuBindGroup(pub(crate) wgpu_core::id::BindGroupId);
impl Resource for WebGpuBindGroup {
  fn name(&self) -> Cow<str> {
    "webGPUBindGroup".into()
  }
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
struct GpuBufferBindingLayout {
  r#type: GpuBufferBindingType,
  has_dynamic_offset: bool,
  min_binding_size: u64,
}

#[derive(Deserialize)]
#[serde(rename_all = "kebab-case")]
enum GpuBufferBindingType {
  Uniform,
  Storage,
  ReadOnlyStorage,
}

impl From<GpuBufferBindingType> for wgpu_types::BufferBindingType {
  fn from(binding_type: GpuBufferBindingType) -> Self {
    match binding_type {
      GpuBufferBindingType::Uniform => wgpu_types::BufferBindingType::Uniform,
      GpuBufferBindingType::Storage => {
        wgpu_types::BufferBindingType::Storage { read_only: false }
      }
      GpuBufferBindingType::ReadOnlyStorage => {
        wgpu_types::BufferBindingType::Storage { read_only: true }
      }
    }
  }
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
struct GpuSamplerBindingLayout {
  r#type: wgpu_types::SamplerBindingType,
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
struct GpuTextureBindingLayout {
  sample_type: GpuTextureSampleType,
  view_dimension: wgpu_types::TextureViewDimension,
  multisampled: bool,
}

#[derive(Deserialize)]
#[serde(rename_all = "kebab-case")]
enum GpuTextureSampleType {
  Float,
  UnfilterableFloat,
  Depth,
  Sint,
  Uint,
}

impl From<GpuTextureSampleType> for wgpu_types::TextureSampleType {
  fn from(sample_type: GpuTextureSampleType) -> Self {
    match sample_type {
      GpuTextureSampleType::Float => {
        wgpu_types::TextureSampleType::Float { filterable: true }
      }
      GpuTextureSampleType::UnfilterableFloat => {
        wgpu_types::TextureSampleType::Float { filterable: false }
      }
      GpuTextureSampleType::Depth => wgpu_types::TextureSampleType::Depth,
      GpuTextureSampleType::Sint => wgpu_types::TextureSampleType::Sint,
      GpuTextureSampleType::Uint => wgpu_types::TextureSampleType::Uint,
    }
  }
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
struct GpuStorageTextureBindingLayout {
  access: GpuStorageTextureAccess,
  format: wgpu_types::TextureFormat,
  view_dimension: wgpu_types::TextureViewDimension,
}

#[derive(Deserialize)]
#[serde(rename_all = "kebab-case")]
enum GpuStorageTextureAccess {
  WriteOnly,
}

impl From<GpuStorageTextureAccess> for wgpu_types::StorageTextureAccess {
  fn from(access: GpuStorageTextureAccess) -> Self {
    match access {
      GpuStorageTextureAccess::WriteOnly => {
        wgpu_types::StorageTextureAccess::WriteOnly
      }
    }
  }
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
struct GpuBindGroupLayoutEntry {
  binding: u32,
  visibility: u32,
  #[serde(flatten)]
  binding_type: GpuBindingType,
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
enum GpuBindingType {
  Buffer(GpuBufferBindingLayout),
  Sampler(GpuSamplerBindingLayout),
  Texture(GpuTextureBindingLayout),
  StorageTexture(GpuStorageTextureBindingLayout),
}

impl TryFrom<GpuBindingType> for wgpu_types::BindingType {
  type Error = AnyError;

  fn try_from(
    binding_type: GpuBindingType,
  ) -> Result<wgpu_types::BindingType, Self::Error> {
    let binding_type = match binding_type {
      GpuBindingType::Buffer(buffer) => wgpu_types::BindingType::Buffer {
        ty: buffer.r#type.into(),
        has_dynamic_offset: buffer.has_dynamic_offset,
        min_binding_size: std::num::NonZeroU64::new(buffer.min_binding_size),
      },
      GpuBindingType::Sampler(sampler) => {
        wgpu_types::BindingType::Sampler(sampler.r#type)
      }
      GpuBindingType::Texture(texture) => wgpu_types::BindingType::Texture {
        sample_type: texture.sample_type.into(),
        view_dimension: texture.view_dimension,
        multisampled: texture.multisampled,
      },
      GpuBindingType::StorageTexture(storage_texture) => {
        wgpu_types::BindingType::StorageTexture {
          access: storage_texture.access.into(),
          format: storage_texture.format,
          view_dimension: storage_texture.view_dimension,
        }
      }
    };
    Ok(binding_type)
  }
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct CreateBindGroupLayoutArgs {
  device_rid: ResourceId,
  label: Option<String>,
  entries: Vec<GpuBindGroupLayoutEntry>,
}

pub fn op_webgpu_create_bind_group_layout(
  state: &mut OpState,
  args: CreateBindGroupLayoutArgs,
  _: (),
) -> Result<WebGpuResult, AnyError> {
  let instance = state.borrow::<super::Instance>();
  let device_resource = state
    .resource_table
    .get::<super::WebGpuDevice>(args.device_rid)?;
  let device = device_resource.0;

  let mut entries = vec![];

  for entry in args.entries {
    entries.push(wgpu_types::BindGroupLayoutEntry {
      binding: entry.binding,
      visibility: wgpu_types::ShaderStages::from_bits(entry.visibility)
        .unwrap(),
      ty: entry.binding_type.try_into()?,
      count: None, // native-only
    });
  }

  let descriptor = wgpu_core::binding_model::BindGroupLayoutDescriptor {
    label: args.label.map(Cow::from),
    entries: Cow::from(entries),
  };

  gfx_put!(device => instance.device_create_bind_group_layout(
    device,
    &descriptor,
    std::marker::PhantomData
  ) => state, WebGpuBindGroupLayout)
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct CreatePipelineLayoutArgs {
  device_rid: ResourceId,
  label: Option<String>,
  bind_group_layouts: Vec<u32>,
}

pub fn op_webgpu_create_pipeline_layout(
  state: &mut OpState,
  args: CreatePipelineLayoutArgs,
  _: (),
) -> Result<WebGpuResult, AnyError> {
  let instance = state.borrow::<super::Instance>();
  let device_resource = state
    .resource_table
    .get::<super::WebGpuDevice>(args.device_rid)?;
  let device = device_resource.0;

  let mut bind_group_layouts = vec![];

  for rid in &args.bind_group_layouts {
    let bind_group_layout =
      state.resource_table.get::<WebGpuBindGroupLayout>(*rid)?;
    bind_group_layouts.push(bind_group_layout.0);
  }

  let descriptor = wgpu_core::binding_model::PipelineLayoutDescriptor {
    label: args.label.map(Cow::from),
    bind_group_layouts: Cow::from(bind_group_layouts),
    push_constant_ranges: Default::default(),
  };

  gfx_put!(device => instance.device_create_pipeline_layout(
    device,
    &descriptor,
    std::marker::PhantomData
  ) => state, super::pipeline::WebGpuPipelineLayout)
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
struct GpuBindGroupEntry {
  binding: u32,
  kind: String,
  resource: ResourceId,
  offset: Option<u64>,
  size: Option<u64>,
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct CreateBindGroupArgs {
  device_rid: ResourceId,
  label: Option<String>,
  layout: ResourceId,
  entries: Vec<GpuBindGroupEntry>,
}

pub fn op_webgpu_create_bind_group(
  state: &mut OpState,
  args: CreateBindGroupArgs,
  _: (),
) -> Result<WebGpuResult, AnyError> {
  let instance = state.borrow::<super::Instance>();
  let device_resource = state
    .resource_table
    .get::<super::WebGpuDevice>(args.device_rid)?;
  let device = device_resource.0;

  let mut entries = vec![];

  for entry in &args.entries {
    let e = wgpu_core::binding_model::BindGroupEntry {
      binding: entry.binding,
      resource: match entry.kind.as_str() {
        "GPUSampler" => {
          let sampler_resource =
            state
              .resource_table
              .get::<super::sampler::WebGpuSampler>(entry.resource)?;
          wgpu_core::binding_model::BindingResource::Sampler(sampler_resource.0)
        }
        "GPUTextureView" => {
          let texture_view_resource =
            state
              .resource_table
              .get::<super::texture::WebGpuTextureView>(entry.resource)?;
          wgpu_core::binding_model::BindingResource::TextureView(
            texture_view_resource.0,
          )
        }
        "GPUBufferBinding" => {
          let buffer_resource =
            state
              .resource_table
              .get::<super::buffer::WebGpuBuffer>(entry.resource)?;
          wgpu_core::binding_model::BindingResource::Buffer(
            wgpu_core::binding_model::BufferBinding {
              buffer_id: buffer_resource.0,
              offset: entry.offset.unwrap_or(0),
              size: std::num::NonZeroU64::new(entry.size.unwrap_or(0)),
            },
          )
        }
        _ => unreachable!(),
      },
    };
    entries.push(e);
  }

  let bind_group_layout = state
    .resource_table
    .get::<WebGpuBindGroupLayout>(args.layout)?;

  let descriptor = wgpu_core::binding_model::BindGroupDescriptor {
    label: args.label.map(Cow::from),
    layout: bind_group_layout.0,
    entries: Cow::from(entries),
  };

  gfx_put!(device => instance.device_create_bind_group(
    device,
    &descriptor,
    std::marker::PhantomData
  ) => state, WebGpuBindGroup)
}
